In many environments where dynamoelectric machines are used, very high power density requirements, along with severe weight, volume and noise requirements, dictate a need for additional cooling of the stator. For example, for shipboard use, direct water-cooling of the dynamoelectric machine is attractive. While water-cooling of stator windings for dynamoelectric machines has been used extensively in the past, very little effort, to applicants' knowledge, has been directed to water-cooling the stator core. Prior stator core cooling has been, for the most part, limited to air and gas cooling. Air and gas cooling requires the use of space blocks or similar assemblies to create passages to allow air/gas movement through the core. Fans are also necessarily employed, typically at both ends of the rotor, to obtain the required flow. These requirements, however, add to the core length, which increases weight and volume. The fans also increase the noise level.
As indicated, prior efforts to water-cool stator cores have been considerably limited. For example, a dynamoelectric machine has been built using an outside diameter water jacket. This, however, did not provide water-cooling within the core itself but only about the core. Additionally, U.S. Pat. No. 3,597,645 discloses a liquid cooling system for the stacks of stator core laminations of a dynamoelectric machine. This patent, however, provides for radial flow paths for the water in hollow cooling pads arranged in sectors about the circumference of the core. Where space, volume and weight as well as noise requirements are a consideration in the design of a dynamoelectric machine, this type of water-cooled stator core is notably deficient.